Many kinds of mixing valves are distinguishable because of their water flow rate, the kind of valve plates used for the regulation of liquid flow, the arrangement of the supply lines and spout outlet, the optional placement of divertors, or the presence of other particular characteristics as required by the laws or regulations of some particular countries. Furthermore, the same mixing valve can behave differently depending on how it is connected to the supply lines if the cartridge is not correspondingly modified.
Up to now there has been the necessity to produce many different cartridges, each one particularly suited to different kinds of mixing valves or to particular installation conditions although the shell, operating mechanism, and other components are not substantially different in different models and are theoretically susceptible to standard construction. The production of many kinds of cartridges, which are different only because of some minor details, causes a cost increase in production, inventory and distribution and causes the plumbers to be supplied with different kinds of cartridges and the risk in choosing from the various cartridges.